2023W2 - Assignment 6_ COMM 191 201 202 2023W2 Application of Statistics in Business
pdf
keyboard_arrow_up
School
University of British Columbia *
*We aren’t endorsed by this school
Course
191
Subject
Communications
Date
Apr 3, 2024
Type
Pages
12
Uploaded by CorporalJellyfishMaster1054
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
1/12
2023W2 - Assignment 6
Due Feb 28 at 11:59p.m.
Points 50
Questions 18
Available Feb 14 at 7a.m. - Feb 28 at 11:59p.m.
Time Limit None
This quiz was locked Feb 28 at 11:59p.m..
Attempt History
Attempt
Time
Score
LATEST
Attempt 1
14,239 minutes
44 out of 50
Score for this quiz: 44 out of 50
Submitted Feb 28 at 9:20a.m.
This attempt took 14,239 minutes.
Question 1
2 / 2 pts
Skewed, because the true proportion is much greater than 0.50.
Symmetric but not normal, because the data are binary.
Correct!
Normal, because of the Central Limit Theorem.
Cannot tell without plotting the raw data.
Question 2
1 / 1 pts
Use this information for Questions 1, 2, 3, 4, 5.
Sampling Distribution of Proportions
A restaurant chain regularly surveys its customers. On the basis of these surveys, the management of
the chain claims that 75% of its customers rate the food as excellent. A consumer testing service wants
to examine this claim. They take a simple random sample of 600 customers and ask them each to rate
the food.
Assume that the restaurant chain’s claim is true (i.e. that the true proportion is indeed 0.75).
What is the general shape of the sampling distribution of the sample proportion of customers who are
satisfied?
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
2/12
Correct!
0.75
0.75 (with margin: 0)
Between 0.7499 and 0.7501
Question 3
1 / 1 pts
Correct!
0.0177
0.0177 (with margin: 0)
0.018 (with margin: 0)
Between 0.017 and 0.018
Question 4
2 / 2 pts
Correct!
0.0023
0.0024 (with margin: 0)
0.0023 (with margin: 0)
0.24 (with margin: 0)
0.23 (with margin: 0)
Between 0.0023 and 0.0024
What is the mean of the sample proportion ?
(Enter the mean to two decimal places, 0.xx.) What is the standard deviation of the sample proportion ?
(Enter the standard deviation to four decimal places 0.xxxx.)
Again assuming that the chain’s claim is true (i.e. that the true proportion is indeed 0.75), what is the
probability that, in a simple random sample of 600 customers, less than 70% rate the food as excellent?
Use the mean and standard deviation you computed above).
(Enter the probability to four decimal places in the format 0.xxxx . Do NOT convert to percentages.)
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
3/12
Question 5
2 / 2 pts
Support
Correct!
Refute
Cannot tell
Question 6
1 / 1 pts
Correct!
0.75
0.75 (with margin: 0)
Question 7
1 / 1 pts
Correct!
0.0137
0.0137 (with margin: 0)
Between 0.0136 and 0.0138
Question 8
1 / 1 pts
Correct!
Suppose that in a random sample of 600 customers, 420 rate the food as excellent. Does this support or
refute the restaurant chain’s claim? Hint: Refer to previous question.
For Questions 6, 7, 8, redo the previous calculations with a simple random sample of size 1000. a.
What is the mean?
(Enter the mean to two decimal places, 0.xx.) b.
What is the new SD?
(Enter the standard deviation to four decimal places 0.xxxx.) c.
What is the new probability that less than 70% rate the food as excellent.
(Enter the probability to four decimal places in the format 0.xxxx . Do NOT convert to percentages.)
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
4/12
0.0001
0.0001 (with margin: 0)
Between 0.0001 and 0.0002
Question 9
4 / 4 pts
Answer 1:
Correct! 92000
Correct!
92000
Correct Answer
92,000
Answer 2:
Correct! 2220
Correct!
2220
Correct Answer
2,220
Question 10
2 / 2 pts
Use this information for Questions 9, 10, 11, 12, 13
Sampling Distribution of Means
The admissions department of University A (UA) claims that the starting salaries of their MBA graduates
are normally distributed with a mean of $92,000 and a standard deviation of $15,700. Similarly, the
admissions department of University B (UB) claims that the starting salaries of their MBA graduates are
normally distributed with a mean of $90,000 and a standard deviation of $19,500. To test these claims a
random sample of 50 UA MBAs and a random sample of 60 UB MBAs are selected.
For University A, what are the mean and standard deviation of the sample mean?
(Enter the mean and standard deviation to the nearest whole number. Do NOT include units!)
Mean = 92000
SD = 2220
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
5/12
Correct!
0.0122
0.0122 (with margin: 0)
1.22 (with margin: 0)
Between 0.012 and 0.013
Question 11
4 / 4 pts
Answer 1:
Correct! 90000
Correct!
90000
Correct Answer
90,000
Answer 2:
Correct! 2517
Correct!
2517
Correct Answer
2,517
Correct Answer
2518
Correct Answer
2,518
For University A, what is the probability that the sample mean starting salary will be less than $87,000?
(Enter the probability to four decimal places in the format 0.xxxx . Do NOT convert to percentages.)
For University B, what are the mean and standard deviation of the sample mean?
(Enter the mean and standard deviation to the nearest whole number. Do NOT include units!)
Mean = 90000
SD = 2517
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
6/12
Question 12
0 / 2 pts
You Answered
0.1171
0.1167 (with margin: 0)
11.67 (with margin: 0)
Between 0.116 and 0.117
Question 13
0 / 2 pts
You Answered
0.4681
0.7244 (with margin: 0)
0.7243 (with margin: 0)
72.44 (with margin: 0)
72.43 (with margin: 0)
Between 0.723 and 0.726
Question 14
2 / 4 pts
For University B, what is the probability that the sample mean starting salary will be less than $87,000?
(Enter the probability to four decimal places in the format 0.xxxx . Do NOT convert to percentages.)
This part is harder: What is the probability that the mean starting salary of UA MBA grads will exceed the
mean starting salary of UB MBA grads?
Hints: Let X
= UA salaries and Y
= UB salaries. Then find Pr(
X
̄
– Ȳ
> 0)
You will need the sampling distribution of the difference of means and the mean and standard deviation
of the difference; then you’re on your way.
(Enter the probability to four decimal places in the format 0.xxxx . Do NOT convert to percentages. Note:
You do not need to provide the mean and standard deviation of the difference; just the probability!)
According to one year's C291 Student Survey, the mean height of males is 177 cm. with a standard
deviation of 7.5 cm. Assume that these results are true for the population of all C291 students. For each
statement, decide whether it is True
or False
. Hint: Use the 68-95-99.7 Rule.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
7/12
Answer 1:
Correct!
True
False
Answer 2:
True
Correct!
False
Answer 3:
You Answered
True
Correct Answer
False
Answer 4:
Correct Answer
True
You Answered
False
Question 15
6 / 6 pts
i. The chance that the height of one randomly chosen male C291 student is between 169.5 and 184.5
is about 68%.
True
ii. The chance that the mean of a random sample of 25 male C291 students is between 169.5 and
184.5 is about 68%.
False
iii. The chance that the height of one randomly chosen male C291 student is between 175.5 and 178.5
is about 68%.
True
iv. The chance that the mean of a random sample of 25 male C291 students is between 175.5 and
178.5 is about 68%.
False
For each of the following situations, choose which type of bias we should be most concerned about:
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
8/12
Answer 1:
Convenience sampling bias
Undercoverage
Sampling error
Stratified random sample
Voluntary response bias
Bad sampling frame
Correct!
Nonresponse bias
None of the other answers
Answer 2:
Convenience sampling bias
Undercoverage
Sampling error
Stratified random sample
Correct!
Voluntary response bias
Bad sampling frame
Nonresponse bias
None of the other answers
Answer 3:
Convenience sampling bias
Correct!
Undercoverage
Sampling error
Stratified random sample
Voluntary response bias
Bad sampling frame
1. A survey about ride-sharing services is sent out to a randomly selected sample of BC residents by
mail and 4.7% of the surveys are returned: → Nonresponse bias
2. A pipeline company runs an ad in a newspaper asking people to sign in to their website to record
their opinions about pipeline expansion: → Voluntary response bias
3. A public opinion survey selects names from a city telephone directory: → Undercoverage
4. A marketing survey from a Vancouver-based clothing company that employees are asked to give to
their friends and families: → Convenience sampling bias
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
9/12
Nonresponse bias
None of the other answers
Answer 4:
Correct!
Convenience sampling bias
Undercoverage
Sampling error
Stratified random sample
Voluntary response bias
Bad sampling frame
Nonresponse bias
None of the other answers
Question 16
10 / 10 pts
Answer 1:
Simple Random Sampling
Stratified Random Sampling
Cluster Random Sampling
Multistage Sampling
Systematic Sampling
Correct!
Convenience Sampling
An accounting firm has 72 members in 6 departments. Each department has 1 senior partner (SP), 2
junior partners (JP) and 9 associates (AS). A sample of 12 of the firm's members will be chosen to attend
a professional conference. Choose the best description of each of these sampling methods.
a. Choose the first 12 names on the alphabetical listing of all 72 of the firm's members. → Convenience
Sampling
b. Choose 1 department at random and select every member of that department. → Cluster Random
Sampling
c. Choose 1 SP at random from the 6 SPs, 2 JPs at random from the 12 JPs, and 9 ASs at random
from the 54 ASs. → Stratified Random Sampling
d. Choose 12 members at random from all 72 of the firm's members. → Simple Random Sampling
e. Rank the firm's members by height and select every sixth person. → Systematic Sampling
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
10/12
Answer 2:
Simple Random Sampling
Stratified Random Sampling
Correct!
Cluster Random Sampling
Multistage Sampling
Systematic Sampling
Convenience Sampling
Answer 3:
Simple Random Sampling
Correct!
Stratified Random Sampling
Cluster Random Sampling
Multistage Sampling
Systematic Sampling
Convenience Sampling
Answer 4:
Correct!
Simple Random Sampling
Stratified Random Sampling
Cluster Random Sampling
Multistage Sampling
Systematic Sampling
Convenience Sampling
Answer 5:
Simple Random Sampling
Stratified Random Sampling
Cluster Random Sampling
Multistage Sampling
Correct!
Systematic Sampling
Convenience Sampling
Question 17
2 / 2 pts
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
11/12
Correct!
Leading questions can introduce strong bias and both of these questions lead to a Yes answer.
The sample was not representative of the population.
There is probably voluntary response bias.
There is probably undercoverage bias.
Question 18
3 / 3 pts
Answer 1:
All 10000 frequent flier customers polled
All airlines that will use the new hubs
All customers in the airline’s database
All customers of the airline
All customers who respond to the survey
All frequent flier customers in the airline’s database
Correct!
All frequent flier customers of the airline
Average number of times plan to use the new hubs
Proportion of 10000 who plan to use one of the new hubs
A survey of the economic attitudes of Europeans was carried out. Of the 2500 adults interviewed, 72%
agreed that “employees with higher performance must get higher pay.” On the other hand 71% agreed
that “everything a society produces should be distributed among its members as equally as possible and
there should be no major differences.” What is the most likely explanation for the contradictory results?
An airline company wants to know what proportion of frequent fliers plan to use one of the airline’s
proposed new hubs in the next six months. Pollsters take a random sample of 10,000 from the database
of all frequent fliers and send them an email message with a request to fill out a survey in exchange for
1500 air miles.
a. What is the population?
All frequent flier customers of the airline
b. What is the sampling frame?
All frequent flier customers in the airline’s database
c. What is the population parameter of interest?
Proportion of all frequent fliers customers who plan to use one of the new hubs
3/24/24, 10:41 AM
2023W2 - Assignment 6: COMM 191 201 202 2023W2 Application of Statistics in Business
https://canvas.ubc.ca/courses/129798/quizzes/676561
12/12
Proportion of all frequent fliers customers who plan to use one of the new hubs
Proportion of respondents who plan to use one of the new hubs
Answer 2:
All 10000 frequent flier customers polled
All airlines that will use the new hubs
All customers in the airline’s database
All customers of the airline
All customers who respond to the survey
Correct!
All frequent flier customers in the airline’s database
All frequent flier customers of the airline
Average number of times plan to use the new hubs
Proportion of 10000 who plan to use one of the new hubs
Proportion of all frequent fliers customers who plan to use one of the new hubs
Proportion of respondents who plan to use one of the new hubs
Answer 3:
All 10000 frequent flier customers polled
All airlines that will use the new hubs
All customers in the airline’s database
All customers of the airline
All customers who respond to the survey
All frequent flier customers in the airline’s database
All frequent flier customers of the airline
Average number of times plan to use the new hubs
Proportion of 10000 who plan to use one of the new hubs
Correct!
Proportion of all frequent fliers customers who plan to use one of the new hubs
Proportion of respondents who plan to use one of the new hubs
Quiz Score: 44 out of 50
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help